Electrolytic apparatus.



Patented Dec. 8, 1908. 4 SHEETS-SHEET 1.

Patented Dec. 8, 1908.

4 SHEETS-SHEET 2,

E. D. CHAPLIN.

ELBGTROLYTIG APPARATUS.

APPLICATION FILED FEB. s, 190e.

906,104. Patented Dec. 8, 190s.

4 SHEETSSHEET 3.

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ELETROLYTIC APPARATUS.

APPLIOATION FILED FEB. s, 190e.

Patented Dee. 8, 1908.

4 SHEETS-SHEET 4.

Figi- Figi- UNTTED sTATEs PATENT oEEIoE.

EDWIN D. CHAPLIN, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO INTERNATIONAL LEAD COMPANIES, A VOLUNTARY ASSOCIATION.

ELECTROLYTIC APPARATUS.

Patented nec. e, 190s.

Application led' February 3, 1906. Serial No. 299,240.

To all 'whom it may concern:

Be it known that I, EDWIN I). CnArLiN, a citizen of the UnitedStates, and a resident of Boston, in the county of Suffolk and State. of Massachusetts, have invented a new and useful Improvement in Electrolytic Apparatus, of which the following is a specification.

My invention relates to apparatus wherei by various electrolytic processes may be carried into effect, and it relates more particularly to an apparatus for producing lead salts by electrolysis.

The object of my invention is to provide a practicable apparatus whereby electrolytic processes, especially processes of producing lead salts by electrolysis, may be efciently carried out on a large commercial scale with minimum labor.

With these objects in view my invent-ion comprises an electrolytic apparatus consisting of a plurality of independent electrolytic units under central control, whereby a single operator may be placed in charge of the enti-re plant and may regulate theoperation thereof; and it comprises also an electrolyzer for each said electrolytic unit having a plurality of cells which are so constructed and arranged that a relatively hi h potential source of electrical energy may t(be connected in series vwith said cells and the resistance of said electrolyzer cannot become sufficiently low to short-circuit said source of electrical energy. n

Other objectsv of my invention will hereinafter appear and will be particularly pointed out in the appended claims.

My invention may best be understood by having reference to the drawings which accompany and form a part of this specification and which illustrate one formof apparatus whereby the hereinbefore stated objects may be realized in practice; although it will be understood that I do not wish to be limited to that particular embodiment of my invention illustrated in said drawings, inasmuch as many modifications may be made therein without departing from `the spirit of my invention.

In the drawings, Figure 1 represents a vertical longitudinal section of an electrolytic p lant embodying the present invention, the section being taken on the line 1-1 ot' Fig. 2, looking in the direction of the art row. Fig. 2 represents a vertical cross-section of said plant. Fig. 3 is a diagram hereinafter referred to for the purpose of more clearly explaining the various steps of a white lead process, which may be carried out with the apparatus shown in Fig. 3. Fig. 4 represents a sectional view of one of the electrolytic cells shown conventionally in Figs. l and. 2, said section being taken on the line 4-4 of Fig. 5. Fig. 5 represents an end view of the cell shown in Fig. 4 and Fig. 6 represents a side view thereof.

Inasmuch as the apparatus constituting the present invention is adapted especially for the electrolytic production of white lead, although of course it is not, limited thereto, I shall first describe one process of making white lead -by electrolysis which may be carried out by means of said apparatus. Referring for this purpose to the ldiagram shown in Fig. 3, which shows the apparatus illustrated in Figs. l and 2 in a conventional manner, 1 represents the supply tank containing an electrolyte which, under the influence of the electric current, will be separated into an alkaline 4hydrate and a solvent of lead, such for example as an aqueous solution of a non-alkaline salt, preferably sodium nitrate; and containing also an oxidizing agent for preventing the formation inthe electrolyte of insoluble basic salts of lead, such for example as an aque# ous solution of a soluble chlorate salt; or else containingan aqueous solution of a soluble salt which, under the influence of the electric current, will become an oxidizing agent, such for example as an aqueous solution of a soluble chlorid salt. refer to the solution in tank l as the neiltral solution and shall assume that it consists of sodium nitrate and sodium chlorid. 3 represents an electrolyzer divided into an anode compartment 3 and a cathode compartment 3, by means of the foram'inous diaphragme 4, 4J, between which 1s formed a compartment for receiving the electrolyte from the tank l through the pipe 2. For the purpose of preventing a mixture of the anolyte and catholyte in the electrolyzer and consequentlyk a precipitation of lead hyd-rate in the electrolyzer, I may maintain a preponderance of pressure on the inner sides of said diaphragme, preferably, by

I shall hereinafterA maintaining the level of the electrolytebetween the diaphragms hi her than the level of the anolyte and catho yte. The level of the electrolyte in the compartment between the diaphragms, is indicated by the dotted line e (see Fig. 4) and the level of the anolyte and catholyte, which is governed by the height of the bends of the outlet pipes 7, 8, 7 8', is indicated by the dotted lines f, f. In order to prevent said outlet pipes from siphoning the liquids out of the electrolyzer, the upper portion of each of said bends may be provided with an opening g, to equalize the atmospheric pressure on the colunms of liquid in the two portions of each of said es. ghe lead to be operated upon is placed in the anode compartment and may form the anode of the electrolyzer. In the present case the lead is shown in the form of a lead pig 5, connected lby the conductor d to the positive pole of the dynamo J, or other suitable source of current. The cathode of the electrolyzer may consist of a plate 6 of copper or other suitable metal, and is connected by the conductor c to the negative pole of said dynamo.

As indicated in Fig. 3, I prefer to employ a number of electrolytic cells arranged at successively lower levels and having their electrodes connected in series with the source of electrical energy. When the electrolyzer 3 is charged with the neutral solution and the electric current is assed therethrough, a soluble acid salt of ead is formed in the anode compartment 3 and an alkaline hydrate, in the present case assumed above, sodium hydrate, is formed in the cathode compartment 3". Presumably lead nitrate is at first formed in the anode compartment and this, by the continued action of the electric current, is converted into lead oxychlorid, which is soluble at the temperature at which the electrolyte is maintained by the steam coil 30 or by other suitablel means. The lead oXychlorid being an acid salt of lead renders im ossible the formation of insoluble basic sa ts of lead.

The solution in the anode compartment 3 of the cell 3, is conveyed by the pipe 8 to the anode compartment 3 of the cell 3, and

the solution in the cathode compartment 3 of the cell 3 is conveyed by the pipe 7 to the compartment between the diaphragms 4, 4 of the cell 3a. The solutions in the anode and cathode compartments of the cell 3ISL are in turn discharged by the pipes 8 7', respectively, to the receptacles 10, 9. The solution of the acid salt of lead .is conveyed from the receptacle 10 to the elevated tank 29 by the pump 26 and the pipe 10', while the alkaline hydrate discharged in the receptacle 9 is conveyed to the elevated tank 27 by the pump 26 and pipe 9. The solutions in the tanks 27 and 29 are discharged through the pipes 20 and 21, respectively, into the precipitating vessel 22, which may bea glass globe, and mixed, thereby producing lead hydrate and a solution which is substantially the original neutral solution,- in the present case, sodium nitrate mixed with sodium chlorate and containing probably some sodium chlorid. The pipe 31 conveys the contents of the precipitating vessel into the tank 19 below. the filter 23, so that the filtrate which passes through said filter may be drawn off from the upper portion of the tank 19 by the pipe 25, and discharged into the original supply tank 1. The lead hydrate is conveyed from tank 19 to the lter press 32 by the pipe 24, and the neutral solution which is squeezed out of it by the filter press, is conveyed by the pipe 33 to the tank n1. The lead hydrate may now be removed from the lter press and carbonated in any suitable manner as hereinafter more fully set forth.

Referring now to Figs. 1 and 2, X represents an electrolytic plant comprising a building having4 five levels which carry the various tanks and receptacles above referred to. The particular plant shown in Figs. 1 and 2 consists of six electrolytic units arranged in two rows of three each. Each unit is independent of every other unit, so that the plant thereby is rendered perfectly extensible without changing any of its operating features. Each unit comprises a supply tank 1, an electrolyzer A, or B, or C, at a lower Ilevel than said tank, an outlet from said tank to said electrolyzer, two vessels 9 and 10, at a lower level than said electrolyzer, outlet pipes 7 and 8 for discharging the alkaline hydrate and the lead solution, respectively, into the tanks 9 and 10, two pumps 26, 26 for elevating the alkaline hydrate from the tank 9 on the ground fioor D to the tank 27 on the top floor H, and for conveyin the 'lead solution from the tank 10 on sai ground ioor to the tank 29 on said top floor, outlets 20 and 21, from said tanks 27 and 29 to a precipitating vessel 22, a filtering tank 19 for receiving the contents of said precipitating vessel,`a pipe 25 for conveying the filtrate to the tank 1, a filter press 32 for receiving the precipitate 'from' the vessel 19, and a pipe 33 for conveyin the filter press tothe tank 1. Each electrolytic unit comprises also a carbon dioxid generator 12, communicating by a pipe 13 with the tank 11 for converting the alkaline hydrate discharged into said tank 11 from the tank 27 by the pipe 28 into sodium bi-carbonate; a tank 15 receiving said sodium bicarbonate from the tank 11, through the pilpe 14 for converting the lead hydrate w ich manually or otherwise is taken from the filter press 32 into lead carbonate; a filmg the liquid recovered from the precipitate' ter press16 receiving the lead carbonate so tank 9, kthe sodum hydrate squeezed out of the lead" carbonate by the filter press 16.

In the particular plant herein illustrated there are six precipitating vessels arranged in two rows of three each, those of one row being numbered 22, and those of the other row being numbered 22. There are, as shown in Fig. 1, two rows of tanks alternately numbered 27 and 29, and each pair of tanks 27, 29, communicates with a different one of the precipitating vessels 22, by means of the outlet pipes 20 and 21, respectively. Each of the pairs of tanks arl. ranged opposite the tanks 27, 29, and one of which, 27', is shown in 2, connects, by means of correspondingly arranged pipes, one of which, 20', is shown in Fig. 2, with a different one of the precipitating vessels 22. As shown in Fig. 1, all the precipitating vessels are arranged close together, so thatI one operator may control by means 'of the valves our', with which said outlet pipes are provided, the operation and output of the entire plant.

The elements shown on the right hand portion of Fig. 2 are identical to those above referred to, which are shown on the left hand portion of said ligure, and are correspondingly numbered with primed numerals. Although I have herein shown but two rows of electrolytic units, each comprising three units, it is apparent that any number off rows having a larger number of units may be employed as for example, four rows of three units each, or of five units each, and that however large the number, the valves u, 'v' may always be so arranged as topermit all the independent units being under central control. It will be apparent also that one electrolytic unit may be shut down for cleaning the same, without interferingwith the operation of the plant as a, whole.

ln contradistinction to electrolytic plants in use at the present time, I prefer to employ a dynamo electric machine J, yor other source of current having a relatively `high potential ascompared to those heretofore employed. It has been found in practice that in carrying out processes of the kind above set forth. a-

multiplication of the electrolytic cells coinprising au electrolyzing battery results in short-circuiting the dynamo or other source of current. Heretofore in such processes,`

each anode compartment of such electrolyzer discharged its contents into a trough running the entire length of the electrolyze-r and each cath-ode compartment discharged its contents into a similar trough. Therefore,

the electrolyzer was to a greater or less degr-shunted by each of said troughs, and

when a sutlicient number of cells were employed to require a generator of relatively high potential, said generator was short-circuited, the current traversing the following path,-from the positive pole to the anode compartment of the first cell, through the pipe which discharges the anolyte into the aforesaid trough, through the trough to the pipe which discharges the contents of the anode compartment of the last cell into said, trough, then to the cathode of said last cell and back to the generator, thereby diverting by means of the trough and the liquid owi'ng therein a large proportion of the current delivered by said dynamo because after the cells have been multiplied to a certain extent, their combined serial resistance is much greater than the resistance of the shunt afforded by said trough.

By arranging the cells which make upthe electrolyzers A, B, C, etc., at successlvely lower levels, and-arranging the pipesS and 7 so that an anode compartment at a higher level will discharge its contents through the short-circuiting the generator. By so constructing and arrangin the elements 3, 3, 3b, etc., of each electro yzer A, B, C, etc., the resistance of said electrolyzer cannot become suiliciently low to short-circuit a source of energy having a potential relatively hi h as compared to those commonly employe For example, the generator J may be an ordinary electric-lighting dynamo, delivering current at 110 volts, or the terminals of the electrolyzer may be connected to an ordinary electric lighting circuit having connections to a power house.

`Then sodium-chlorid, or any other suitable soluble chlorid salt is employed in connection With the aqueous solution of a nitrate of a-n alkaline base to prevent the formation of insoluble lead salts in the electrolyzer,

lead chlorid probably is formed at one stage' of the process and as this is insoluble at A ordinary temperatures, it is necessary to heat the neutral solution, as more fully set forth in United States Letters Patent N o. 67 5,555, dated June 1, 1901, granted to H. G. Hall'oran and myself. A convenient means of maintaining the electrolyte at the desired temperature consists in the .steam coil 30. shown in Fig. 3. lt will be understood of course that each tank 1 will be provided with such steam coil and that all coils may` he connected in series witha steam generator. Another object in heating the electrolyte is to provide a hot solution for treating the lead hydrate in the tank 15, inasmuch as a hydrated carbonate of lead is thereby produced.

Although for the purpose of more fully disclosing my invention I have described the same in connection with a process of making .white lead in which lead hydrate is first produced and is afterward carbonated, it will be understoodthat the electrolytic apparatus herein described is adapted to be used for carrying out direct processes of elect-rolytically making white lead or processes in which thelead carbonate is precipifated directly from a solution of a soluble salt of lead. Also it will be understood that my invention is not limited to processes of making lead carbonate by electrolysis, inasmuch as it is well adapted for producing other salts of lead, such as lead chromate, lead oXid,l etc. Furthermore in its broad aspects, my invention is not necessarily limited to processes for producing lead salts by electrolysis inasmuch as many other electrolytic processes may be carried into effect thereby. y

I claim:

1. In an apparatus for producing white lead by electrolysis, a neutral solution tank, an electrolyzer at a lower level than said tank, an outlet from said tank to said electrolyzer, two vessels at a lower level than said electrolyzer, outlets from the anode and cathode compartments, respectively, of said electrolyzer to said vessels, means for elevating the liquids discharged into said vessels from said anode and cathode compartments, each to a separate one of a pair of tanks located at a higher level than the aforesaid neutral solution tank, outlets from said pair ot' tanks to a precipitating vessel, means in said outlets for controlling the flow of liquids therethrough, said means being located so as to be within the control of a single operator, outlets fromsaid precipitating vessel to a filtering tank located at a`lower level than said precipitating vessel and at a higher level than the aforesaid neutral solution tank, and an outlet for the filtrate in said filtering tank to said neutral solution tank.

2. In an apparatus for producing white lead by electrolysis, a neutral solution tank, an electrolyzer at a lower level than said tank, an outlet from said tank to said electrolyzer, two vessels at a lower level than said electrolyzer, outlets from the anode and cathode compartments, respectively, of said electrolyzer lto said vessels, means for elevating the liquids. discharged into said vessels from said anode andncathode compartments, each/to a separate one of a pair of tanks located at a higher level than the aforesaid neutral solution tank, outlets from said pair of tanks to a precipitating vessel, outlets in said an electrolyzer from said precipitating vessel to a filtering tank located at a lower level than saidprecipitating vessel and at a higher level than the aforesaid neutral solution tank, and an outlet for the filtrate in said filtering tank to said neutral solution tank.

8. In an apparatus for producing lead salts by electrolysis, a plurality of electrolyzing units, a plurality of pairs of tanks, means for conveying the contents of the anode and cathode compartments, respectively, of each electrolyzing unit to each member of a dierent one of said pairs of tanks, a plurality of precipitating vessels, each associated and operatlvely connected with a different one of said pairs of tanks, and means located so as to be under the control of a single operator for regulating the fiow of liquids from each of said pairs of tanks into a different one of said precipitating vessels.

Li. In an electrolytic apparatus, a rela-- tively high potential electrical generator, an electrolyzer comprising a plurality of cells arranged at successively lower levels, means dividing each cell into an anode compartment, a cathode compartment and an intermediate compartment, pipe connections from the anode compartment of each cell to the anode compartment of the cell at the next lower level, and other pipe connections Jfrom the cathode compartment of each cell to the intermediate compartment of each cell at the next lower level, -and means connecting said cells in series with said enerator.

5. In an apparatus or producing white lead by electrolysis, a neutral solution tank, an electrolyzer at a lower level-than said tank, an outlet from said tank to said electrolyzer, two vessels at a lower level than said electrolyzer, outlets from the anode and cathode compartments, respectively, of said electrolyzer to said vessels, means for elevating the liquids discharged into said vessels from said anode and cathode compartments, each to a separate one of a pair of tanks located at a higher level than the aforesaid neutral solution tank, outlets from said pair of tanks to a precipitating vessel, means outlets for controlling the flow ot liquids therethrough, 'said means belngl l'ocated so as to be within the control or a single operator, and outlets from said' preclpitating vessel to a filtering tank located at a lower level than said precipitating vessel.

6. In an apparatus for producing vwhite lead by electrolysis, a neutral solution tank, at a lower level than said tank, an outlet vfrom said tank to said electrolyzer, two vessels at a lower level than said electrolyzer, outlets from the anode ,and cathode compartments, respectively, of said electrolyzer to said vessels, means Jfor elevating the liquids discharged into said vessels from said anode and cathode compartments, 4

each to a separate one of a pair of tanks located at a higher level than the aforesaid neutral solution tank, outlets from said pair of tanks to a recipitating vessel, means in said outlets or controlling the flow of liquids therethrough, said means being located so as to be Within the control of a single operator, outlets from said precipitating vessel to a filtering tank located at a lower level than said precipitating vessel, and means for conveying the filtrate from said filtering tank to said neutral solution tank.

7. In an apparatus for producing White lead by electrolysis, a neutral solution tank, an `electrolyzer at a lower level than said tank, an outlet from said tank to said electrolyzer, two vessels at a lower level than said electrolyzer, outlets from the anode and cathode compartments, respectively, of said electrolyzer to said vessels, means for elevating the liquids discharged into said Vessels from said anode and cathode compartments, each to a separate one of a pair of tanks located at a higher level than the aforesaid neutral solution tank, outlets from said pair of tanks to a precipitating vessel, and outlets from said precipitating vessel to a filtering tank located at a lower level than said precipitating vessel:y v f 8. In an ap aratus for producing white lead by electro ysis, a neutral solution tank, an electrolyzer at e lower level than said tank, an outlet from said tank to said electrolyzer, two vessels at a lower level than said electrolyzer, outlets from the anode and cathode compartments, respectively, of said electrolyzer to said vessels, means for elevating the liquids discharged into said vessels from the anode and cathode compartments, each to a separat-e one of a pair of tanks located at a higher level than the aforesaid neutral solution tank, outlets from said pair of tanks to a precipitating vessel, outlets from said precipitating vessel to a filtering tank located at a lower level than said precipitating vessel and means for conveying the filtrate from said filtering tank to said neutral solution tank.

9. In an apparatus for producing lead salts by electrolysis, an electrolyzing unit, a pair of tanks, means for conveying the contents of the anode and cathode compartments, respectively, of said electrolyzing unit each to a different one of said tanks, a precipitating vessel associated and operatively connected with said pair of tanks, and means for regulating the flow of liquids from said pair of tanks into said precipitating Vessel.

In testimony whereof, I have hereunto subscribed my name this 20th day of J anuary 1906.

EDWIN D. CHAPLIN. Witnesses:

CHARLES C. KURTZ, GEO. K. WooDwoRTH. 

